How can I compare if two dates in JS are equal?

Question

I have two dates in a form:

var date = Wed Oct 07 2015 19:48:08 GMT+0200 (Central European Daylight Time);

var dateOne = new Date(date);
var dateTwo = new Date();

if (dateOne == dateTwo )
    alert ("equals");
else{
    alert("not equal");
}

and even if I set up the date on client's site to Wed Oct 07 2015 19:48:08 GMT+0200 (Central European Daylight Time) I'm still getting not equal...

Even when I do this:

var data1 = new Date();
var data2 = new Date();



if (data1 == data2)
    alert ("equals");
else{
    alert("not equal");
}

The not equal appears again. What am I doing wrong?

score 12 · Accepted Answer · answered Oct 07 '15 at 17:53

12

When you compare objects with ==, it checks to see if they are the same object, not just the same value.

You can try to get the difference between them to see if it's 0:

if (data1-data2 === 0)
    alert ("equals");
else{
    alert("not equal");
}

answered Oct 07 '15 at 17:53

gen_Eric

223,194
41
299
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Maciej · Answer 2 · 2015-10-07T18:09:11.357

3

Probably they differ in miliseconds. Trim miliseconds before comparing if you don't need that precision.

date1.setMilliseconds(0); date2.setMilliseconds(0);

edited Oct 07 '15 at 18:09

answered Oct 07 '15 at 17:56

Maciej

153
9

and in that case how can I trim them for those milliseconds? I'm only interested in comparing date and time with a precision for seconds... – randomuser1 Oct 07 '15 at 18:05
I updated my answer. – Maciej Oct 07 '15 at 18:09

score 2 · Answer 3 · answered Oct 07 '15 at 17:53

2

Every time you call Date() you get a different date because time is passing. If you set date2 = date1, only then will they be equal. The date has a millisecond component.

answered Oct 07 '15 at 17:53

kasia

111
4

How can I compare if two dates in JS are equal?

3 Answers3